/* Copyright (C) 2017-2099 All right reserved
 * For free
 *
 * @file md5.c
 * @brief  md5 in c
 * @author qigaohua, qigaohua168@163.com
 * @version 0.0.1
 * @date 2020-10-29
 */


#include <string.h>
#include <stdio.h>
#include "md5.h"



#ifdef OPENSSL
#include <openssl/md5.h>

#else

#define F(x,y,z) ((x & y) | (~x & z))
#define G(x,y,z) ((x & z) | (y & ~z))
#define H(x,y,z) (x^y^z)
#define I(x,y,z) (y ^ (x | ~z))
#define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))
#define FF(a,b,c,d,x,s,ac) \
	{ \
		a += F(b,c,d) + x + ac; \
		a = ROTATE_LEFT(a,s); \
		a += b; \
	}
#define GG(a,b,c,d,x,s,ac) \
	{ \
		a += G(b,c,d) + x + ac; \
		a = ROTATE_LEFT(a,s); \
		a += b; \
	}
#define HH(a,b,c,d,x,s,ac) \
	{ \
		a += H(b,c,d) + x + ac; \
		a = ROTATE_LEFT(a,s); \
		a += b; \
	}
#define II(a,b,c,d,x,s,ac) \
	{ \
		a += I(b,c,d) + x + ac; \
		a = ROTATE_LEFT(a,s); \
		a += b; \
	}

// void MD5Transform(unsigned int state[4],unsigned char block[64]);
// void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);
// void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);

unsigned char PADDING[] = {
	0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};

void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len) {
	unsigned int i = 0,j = 0;
	while(j < len) {
		output[j] = input[i] & 0xFF;
		output[j+1] = (input[i] >> 8) & 0xFF;
		output[j+2] = (input[i] >> 16) & 0xFF;
		output[j+3] = (input[i] >> 24) & 0xFF;
		i++;
		j+=4;
	}
}
void MD5Decode(unsigned int *output, const unsigned char *input,unsigned int len) {
	unsigned int i = 0,j = 0;
	while(j < len) {
		output[i] = (input[j]) | (input[j+1] << 8) | (input[j+2] << 16) | (input[j+3] << 24);
		i++;
		j+=4;
	}
}
void MD5Transform(unsigned int state[4], const unsigned char block[64]) {
	unsigned int a = state[0];
	unsigned int b = state[1];
	unsigned int c = state[2];
	unsigned int d = state[3];
	unsigned int x[64];

	MD5Decode(x,block,64);

	FF(a, b, c, d, x[ 0], 7, 0xd76aa478);
	FF(d, a, b, c, x[ 1], 12, 0xe8c7b756);
	FF(c, d, a, b, x[ 2], 17, 0x242070db);
	FF(b, c, d, a, x[ 3], 22, 0xc1bdceee);
	FF(a, b, c, d, x[ 4], 7, 0xf57c0faf);
	FF(d, a, b, c, x[ 5], 12, 0x4787c62a);
	FF(c, d, a, b, x[ 6], 17, 0xa8304613);
	FF(b, c, d, a, x[ 7], 22, 0xfd469501);
	FF(a, b, c, d, x[ 8], 7, 0x698098d8);
	FF(d, a, b, c, x[ 9], 12, 0x8b44f7af);
	FF(c, d, a, b, x[10], 17, 0xffff5bb1);
	FF(b, c, d, a, x[11], 22, 0x895cd7be);
	FF(a, b, c, d, x[12], 7, 0x6b901122);
	FF(d, a, b, c, x[13], 12, 0xfd987193);
	FF(c, d, a, b, x[14], 17, 0xa679438e);
	FF(b, c, d, a, x[15], 22, 0x49b40821);

	GG(a, b, c, d, x[ 1], 5, 0xf61e2562);
	GG(d, a, b, c, x[ 6], 9, 0xc040b340);
	GG(c, d, a, b, x[11], 14, 0x265e5a51);
	GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa);
	GG(a, b, c, d, x[ 5], 5, 0xd62f105d);
	GG(d, a, b, c, x[10], 9,  0x2441453);
	GG(c, d, a, b, x[15], 14, 0xd8a1e681);
	GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8);
	GG(a, b, c, d, x[ 9], 5, 0x21e1cde6);
	GG(d, a, b, c, x[14], 9, 0xc33707d6);
	GG(c, d, a, b, x[ 3], 14, 0xf4d50d87);
	GG(b, c, d, a, x[ 8], 20, 0x455a14ed);
	GG(a, b, c, d, x[13], 5, 0xa9e3e905);
	GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8);
	GG(c, d, a, b, x[ 7], 14, 0x676f02d9);
	GG(b, c, d, a, x[12], 20, 0x8d2a4c8a);


	HH(a, b, c, d, x[ 5], 4, 0xfffa3942);
	HH(d, a, b, c, x[ 8], 11, 0x8771f681);
	HH(c, d, a, b, x[11], 16, 0x6d9d6122);
	HH(b, c, d, a, x[14], 23, 0xfde5380c);
	HH(a, b, c, d, x[ 1], 4, 0xa4beea44);
	HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9);
	HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60);
	HH(b, c, d, a, x[10], 23, 0xbebfbc70);
	HH(a, b, c, d, x[13], 4, 0x289b7ec6);
	HH(d, a, b, c, x[ 0], 11, 0xeaa127fa);
	HH(c, d, a, b, x[ 3], 16, 0xd4ef3085);
	HH(b, c, d, a, x[ 6], 23,  0x4881d05);
	HH(a, b, c, d, x[ 9], 4, 0xd9d4d039);
	HH(d, a, b, c, x[12], 11, 0xe6db99e5);
	HH(c, d, a, b, x[15], 16, 0x1fa27cf8);
	HH(b, c, d, a, x[ 2], 23, 0xc4ac5665);


	II(a, b, c, d, x[ 0], 6, 0xf4292244);
	II(d, a, b, c, x[ 7], 10, 0x432aff97);
	II(c, d, a, b, x[14], 15, 0xab9423a7);
	II(b, c, d, a, x[ 5], 21, 0xfc93a039);
	II(a, b, c, d, x[12], 6, 0x655b59c3);
	II(d, a, b, c, x[ 3], 10, 0x8f0ccc92);
	II(c, d, a, b, x[10], 15, 0xffeff47d);
	II(b, c, d, a, x[ 1], 21, 0x85845dd1);
	II(a, b, c, d, x[ 8], 6, 0x6fa87e4f);
	II(d, a, b, c, x[15], 10, 0xfe2ce6e0);
	II(c, d, a, b, x[ 6], 15, 0xa3014314);
	II(b, c, d, a, x[13], 21, 0x4e0811a1);
	II(a, b, c, d, x[ 4], 6, 0xf7537e82);
	II(d, a, b, c, x[11], 10, 0xbd3af235);
	II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb);
	II(b, c, d, a, x[ 9], 21, 0xeb86d391);
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
}

void MD5_Init(MD5_CTX *context) {
	context->count[0] = 0;
	context->count[1] = 0;
	context->state[0] = 0x67452301;
	context->state[1] = 0xEFCDAB89;
	context->state[2] = 0x98BADCFE;
	context->state[3] = 0x10325476;
}

void MD5_Update(MD5_CTX *context, const unsigned char *input,unsigned int inputlen)
{
	unsigned int i = 0,index = 0,partlen = 0;
	index = (context->count[0] >> 3) & 0x3F;
	partlen = 64 - index;
	context->count[0] += inputlen << 3;
	if(context->count[0] < (inputlen << 3)) {
		context->count[1]++;
	}
	context->count[1] += inputlen >> 29;

	if(inputlen >= partlen) {
		memcpy(&context->buffer[index],input,partlen);
		MD5Transform(context->state,context->buffer);
		for(i = partlen;i+64 <= inputlen;i+=64) {
			MD5Transform(context->state,&input[i]);
		}
		index = 0;
	} else {
		i = 0;
	}

	memcpy(&context->buffer[index],&input[i],inputlen-i);
}

void MD5_Final(unsigned char digest[16], MD5_CTX *context)
{
	unsigned int index = 0,padlen = 0;
	unsigned char bits[8];
	index = (context->count[0] >> 3) & 0x3F;
	padlen = (index < 56)?(56-index):(120-index);
	MD5Encode(bits,context->count,8);
	MD5_Update(context,PADDING,padlen);
	MD5_Update(context,bits,8);
	MD5Encode(digest,context->state,16);
}

#endif



int md5_p(const unsigned char *in, char *out, int outsize)
{
    if (!in || outsize < MD5_PRINT_CHARS) return -1;

    char *ptr = out;

    for (int i = 0; i < MD5_OUTPUT_DIGEST; i++) {
        snprintf(ptr+i*2, outsize-i*2, "%02x", in[i]);
    }

    return 0;
}


int md5_s(const char *str, int slen, unsigned char *out, int outsize)
{
    if (!str || outsize < 16) return -1;

    MD5_CTX ctx;
    MD5_Init(&ctx);
    MD5_Update(&ctx, str, slen);
    MD5_Final(out, &ctx);
    return 0;
}


int md5_f(const char *file, unsigned char *out, int outsize)
{
    if (!file || outsize < 16) return -1;

    MD5_CTX ctx;
    char readbuf[1024] = {'\0'};
    int  readlen;
    FILE *fp;
    unsigned char *ptr = out;

    if (NULL == (fp = fopen(file, "rb"))) {
        return -2;
    }

    MD5_Init(&ctx);

    while(0 < (readlen = fread(readbuf, 1, 1024, fp))) {
        MD5_Update(&ctx, readbuf, readlen);
    }

    MD5_Final(ptr, &ctx);
    fclose(fp);

    return 0;
}


int md5_s16p(const char *str, int slen, unsigned char *out, int outsize)
{
    if (!str || outsize < MD5_PRINT_CHARS) return -1;

    int i;
    unsigned char md5[MD5_OUTPUT_DIGEST] = {'\0'};
    unsigned char *ptr = out;

    MD5_CTX ctx;
    MD5_Init(&ctx);
    MD5_Update(&ctx, str, slen);
    MD5_Final(md5, &ctx);

    for (i = 0; i < MD5_OUTPUT_DIGEST; i++) {
        snprintf(ptr+i*2, outsize-i*2, "%02x", md5[i]);
    }
    return 0;
}


int md5_f16p(const char *file, unsigned char *out, int outsize)
{
    if (!file || outsize < MD5_PRINT_CHARS) return -1;

    FILE *fp;
    MD5_CTX ctx;
    char readbuf[1024] = {'\0'};
    int  readlen, i;
    unsigned char md5[MD5_OUTPUT_DIGEST] = {'\0'};
    unsigned char *ptr = out;

    if (NULL == (fp = fopen(file, "rb"))) {
        return -2;
    }

    MD5_Init(&ctx);
    while(0 < (readlen = fread(readbuf, 1, 1024, fp))) {
        MD5_Update(&ctx, readbuf, readlen);
    }
    MD5_Final(md5, &ctx);

    fclose(fp);

    for (i = 0; i < MD5_OUTPUT_DIGEST; i++) {
        snprintf(ptr+i*2, outsize-i*2, "%02x", md5[i]);
    }

    return 0;
}


#define MD5_TEST
#ifdef MD5_TEST

int main(int argc, char *argv[])
{
    const char *filename = "md5.c";
    const char *string   = "test md5";
    unsigned char out[MD5_OUTPUT_DIGEST+1];
    char pstr[MD5_PRINT_CHARS+1];

    if (0 > md5_f(filename, out, 16))
    {
        printf("md5_f err");
    }
    out[MD5_OUTPUT_DIGEST] = '\0';
    md5_p(out, pstr, 33);
    pstr[MD5_PRINT_CHARS] = '\0';
    printf("file(%s) md5: %s\n", filename, pstr);


    memset(pstr, '\0', sizeof(pstr));
    if (0 > md5_s(string, strlen(string), out, 16))
    {
        printf("md5_f err");
    }
    out[MD5_OUTPUT_DIGEST] = '\0';
    md5_p(out, pstr, 33);
    pstr[MD5_PRINT_CHARS] = '\0';
    printf("string(%s) md5: %s\n", string, pstr);


    memset(pstr, '\0', sizeof(pstr));
    md5_f16p(filename, pstr, sizeof pstr);
    pstr[MD5_PRINT_CHARS] = '\0';
    printf("file(%s) md5: %s\n", filename, pstr);


    memset(pstr, '\0', sizeof(pstr));
    md5_s16p(string, strlen(string), pstr, sizeof pstr);
    pstr[MD5_PRINT_CHARS] = '\0';
    printf("string(%s) md5: %s\n", string, pstr);

    return 0;
}

#endif


